Brewing with enzymes - Enzymes in Food Technology - page 183

Common brewing adjuncts available (adapted from Goode and Arendt 8 ). Table 8.11

Whole cereal Barley, wheat, sorghum, triticale, maize, millet, buckwheat

Grits Maize, rice, sorghum, barley

Flaked Corn, rice, barley, oats

Torrified/micronized Corn, barley, wheat

Extrusion cooked Maize, rice, sorghum, wheat

Flour/starch Corn, wheat, rice, potato, cassava, soya, sorghum

Syrup Corn, wheat, barley, potato, sucrose

Malted cereals Wheat, oats, rye, sorghum, millet

Malted pseudo cereals Buckwheat, quinoa

for brewing adjuncts are barley, maize, rice, sorghum and wheat. Table 8.9 gives an outline
of the main adjunct types, which are currently available to the international brewing industry.
The type of adjunct available to an individual brewer largely depends on the geographical
location of that brewery. Likewise, the physicochemical properties of that adjunct (Table
8.9) will dictate its addition rates to a grist recipe, its time of addition and how it will be
processed. This section will cover the basics of adjunct brewing. The reader is referred to
broader brewing texts 8 for a more comprehensive review of adjuncts and their role in brewing.

8.4.1 Brewing with raw barley as adjunct
The use of barley over other cereal adjuncts offers significant advantages to the brewer. Since
its starch has a similar gelatinization temperature (53-58 ◦ C) to malted barley (61-65 ◦ C)
it can be easily be incorporated into conventional malted barley mashing procedures. Its
endogenous β-amylase ensures maltose production during mashing. Likewise, the presence
of a husk can aid mash filtration through a traditional lauter tun.
As covered earlier in the chapter, the endosperm cell wall structure of raw barley presents
a challenge to the brewer. Careful selection and application of commercial enzymes can
alleviate the difficulties encountered. This will ensure good yields, easy process ability and
good quality beer. Raw barley grain is abrasive and difficult to mill, resulting in a high
percentage of fine material which can give problems during lautering. Due to its low levels
of essential enzymes (α-amylase, proteases and β-glucanases) together with a relatively
inaccessible starchy endosperm, high inclusions of unmalted barley ( 20%) in the mash

(without the aid of commercial enzymes) can lead to problems such as low extract yields,
high wort viscosities, decreased rate of lautering, fermentation problems and beer haze
problems. In recent years, an increased knowledge of the structural complexity of the barley
starchy endosperm cell wall membranes 5-7,9 together with their native enzyme inhibitors has
enabled a more specific approach by enzyme producers to increase process ability of raw
barley adjunct.
When brewing with barley as adjunct together with malted barley, increases in the level
of barley adjunct can result in decreases in extract recovery, wort α-amino nitrogen, fer-
mentability and increases in wort viscosity and β-glucan levels if commercial enzyme levels
are not optimized. While increases in wort amino acid levels result from inclusions of higher
levels of malted barley, the endogenous malt enzymes exhibit very poor raw barley protein
and starch hydrolyzing ability. Likewise, the endogenous malt amylases have been reported
to exhibit very poor raw barley starch hydrolyzing ability. As the level of malt is increased,
their raw barley hydrolytic effects decrease.

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